Genetic diversity and our control of it

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Diversity Definitions

Genetic diversity - variety of genes of all individuals in a species

Biodiversityrange and variety of genes, species and habitats within a specific region

Species diversity - number of species and number of individuals in each one in a community

Habitat diversity - number and range of different habitats in one region

Gene pool - total number of genes in an interbreeding population

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Genetic Diversity

  • Describes the variety of alleles in a species or population. All members will have the same genes but different alleles
  • Whereas the DNA of different species varies a lot as don't have the same genes. The closer related to species are, the more DNA they'll share
  • Genetic diversity is increased by mutations in the DNA forming new alleles and when individuals of the same species from another population migrate and reproduce, intorducing new alleles

Genetic Bottlenecks

  • Causes a massive reduction in population, reducing genetic diversity
  • When masses of the population die beore reproducing due to drastic event (eg. disease or hunting) and a new population is created by the reproduction of the few survivors. new population has very small variety in alleles

Founder Effect

  • When just a few members of a population start their own colony. Usually due to separation by geographic separation or migration, sometimes in humans religion.
  • Greatly reduces diversity and increased inbreeding increases risk of genetic disease
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Selective Breeding

Selective breeding of plants and animals by humans has resulted in reduced genetic diversity

It involves selecting which type of animal or strain of plant reproduce together to produce offspring with desired characteristics and a high-yielding breed

It reduces genetic diversity as once offspring with the desired characteristics have been produced,only that breed will be reproduced, meaning only organisms with similar alleles are bred. This leads to a type of bottleneck

Ethical Issues

  • For: Produces higher-yielding animals + plants
  • Priduces breeds used to produce animals + plants resistant to disease so owners spend less money on drugs and pesticides
  • Against: The selective characteristics can cause health problems. Eg. dairy cows with more milk can become lame due to extra weight
  • It reduces genetic diversity meaning lack of variety in alleles makes breed suceptible to disease
  • It goes against religious beliefs, creating new breeds is seeing as playing God
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